Cannabis
weed · skunk · hash · resin
What does current UK evidence show?
CSEW continues to show cannabis as the most prevalent illicit drug. Household-survey prevalence should not be used as a proxy for potency, dependence or severe harm.
Overview
Identity, legal classification, form and pharmacological context
- Drug category
- Cannabinoids
- Common names
- weed, skunk, hash, resin
- Typical forms
- Herbal cannabis, resin, oils, vape liquids and edible preparations
- Routes
- Usually smoked, vaped or swallowed, depending on the preparation
- UK legal classification
- Class BCannabis, cannabis resin and cannabis oil are controlled; authorised cannabis-based medicines have separate schedules.Check government source ↗
- Concise pharmacology
- THC acts on cannabinoid receptors and produces psychoactive effects; CBD has different effects. Potency and route influence intoxication.
Main harms
Concise clinical and polydrug picture
Anxiety or panic, impaired coordination and increased heart rate can occur; some people experience transient psychotic symptoms. Accidental injury risk rises with impairment.
Frequent use can lead to dependence. Smoking damages the airways, and regular use is associated with mental-health harms in susceptible people; risk varies with age, potency and pattern.
Irritability, sleep problems, low mood and craving can follow frequent use.
Alcohol and other drugs can increase impairment and unpredictable effects.
Smoking exposes the airways to combustion products. Edibles can have delayed effects and uncertain strength, while unregulated vapes may contain unexpected compounds.
Current intelligence status
Assessment, confidence and direction
CSEW continues to show cannabis as the most prevalent illicit drug. Household-survey prevalence should not be used as a proxy for potency, dependence or severe harm.
Reason: Direct official statistics or confirmed analytical evidence support the defined signal. Interpretation remains limited to each source’s geography, period and method.
Principal source limits: Household survey for England and Wales; it under-represents some high-risk populations and does not cover the whole UK. Covers children in specialist treatment in England; substances can overlap and are not prevalence estimates.
Geography and reference periods are given in each linked source card below. The rating is an editorial evidence judgement, not a probability, clinical risk score or TD priority.The assessment reflects the latest linked evidence and is not a universal severity rating.
Operational implications
Evidence-supported prompts for professional response
Plan proportionate early intervention and treatment around frequency, impairment and mental-health need rather than use alone.
Record substance, sold identity, route, frequency and combinations; review physical, mental-health and dependence needs.
Use symptom-led assessment and escalate reduced consciousness, seizures, overheating, chest pain or severe agitation.
Link early identification with safeguarding and age-appropriate treatment without presenting population use as individual risk.
Related intelligence
Continue into connected platform evidence
Sources & limitations
Direct evidence links, reference periods and status
Drug misuse in England and Wales
Published11 Dec 2025Reference periodYear ending March 2025
Household survey for England and Wales; it under-represents some high-risk populations and does not cover the whole UK.Children's substance misuse treatment statistics
Published04 Dec 2025Reference periodEngland · 2024–25
Covers children in specialist treatment in England; substances can overlap and are not prevalence estimates.Cannabis: effects and risks
PublishedSource page undatedReference periodUK public health advice
Individual risks vary with potency, age, frequency and vulnerability.